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Energies and mechanical properties of interfaces from ab-initio calculations and their use in mesoscale models
- Date: 26.02.2015
- Place: Thomas Young Centre, London, UK
Highly accurate ab-initio density functional theory (DFT) calculations of interface energies and mechanical properties, e.g. the interfacial tensile and shear strength, are nowadays state of the art. One of the actual challenges is to derive meaningful relationships between these properties which can then be used to make predictions on the mechanical behaviour of realistic microstructures, e.g. by using them in mesoscale simulations. To this end we have to understand the interrelation between interface structure, chemistry, and energy, as well as that between intrinsic material and interface properties and the mechanical behaviour (such as sliding resistance and deformation mechanisms) of interfaces. Furthermore, we need strategies to extrapolate our DFT findings to finite temperatures. In our work at ICAMS, we are tackling this challenge from different sides. On the one hand we calculate intrinsic grain boundary properties for varying interface structure or chemistry, on the other hand we carry out molecular dynamics simulations of bicrystal shear for different interfaces at different temperatures. In the presentation I will discuss to which extend we can draw conclusions from the outcome of the former on the processes occurring in the latter by looking at the mechanical shear behaviour of interfaces in face centered cubic Al as well as TiAl in the L1_0 structure.